<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
  <form>
    <or>
      <li>email</li>
      <li th:text="${subject[0]}"></li>
    </or>
  </form>

</body>
<script type="text/javascript">
    window.onload = function (){
        var str = [[${subject}]];
        console.log(str[0]);
    }
</script>
</html>